The class of polymers o: carbon monoxide and olefin(s) has been known a number of years. Early processes for the production of such polymers were typically free radical processes as illustrated by Brubaker, U.S. Pat. No. 2,495,286. The polymeric products of such processes were typically relatively low in carbon monoxide content.
More recently, processes for the production of polymers of carbon monoxide and ethylenically unsaturated hydrocarbon have been developed wherein the polymer product is a linear alternating polymer of carbon monoxide and ethylenically unsaturated hydrocarbon. Such processes typically employ a Group VIII transition metal compound or complex as catalyst. Nozaki discloses the use of a HPd(CN)3 catalyst in U.S. Pat. No. 3,835,123, a tetrakis(triarylphosphine) palladium catalyst in U.S. Pat. No. 3,698,460, and the use of an arylphosphine complex of palladium moieties employed in conjunction with inert solvents in U.S. Pat. No. 3,694,412. Shryne et al., U.S. Pat. No. 3,984,388 use nickel cyanide or tetracyanonickelate salts as catalyst. U.K. 1,081,304 teaches alkylphosphine complexes of palladium, and Sen, Chemtech. January 1986, pp. 48-51 describes the use of palladium or rhodium catalysts.
A recently developed process which is becoming of greater interest is described in published European Patent Application Nos. 121,965 and 181,014. These processes employ a catalyst composition formed from a Group VIII metal salt wherein the metal is palladium, cobalt or nickel, the anion of certain strong acids and a bidentate ligand of phosphorus, arsenic or antimony.
Linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon which are produced in the presence of a transition metal catalyst will typically contain some residues of the catalyst in the polymer product. If such residues are present in too great a concentration, the properties of the polymer may be adversely effected. Polymer with too great a residue of transition metal will often be discolored and may be unduly vulnerable to degradation initiated by heat or light. It would be of advantage to provide a process of reducing the level of catalyst residues in such linear alternating polymers.